<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>rem适配方案</title>
    <style>
        @media screen and (min-width:320px) {
            html{
                font-size: 21.33px;
            }
        }
        @media screen and (min-width:750px){
            html{
                font-size: 50px;
            }
        }
        div{
            width: 2rem;
            height: 2rem;
            background-color: pink;
        }

    </style>
</head>
<body>
    <div></div>
</body>
</html>